In preparation for a manual on the lichens
of Minnesota numerous new collections have
been made in many parts of the state and most
of Fink's Minnesota collections have been re-
studied. There are about 35,000 Minnesota collections in the herbarium and the lichen flora has increased to over 700 species. These preliminary keys have been prepared as an aid to further work on this flora and also for the use of students studying lichens in this area. The task of
identifying the Minnesota lichens and preparation of the keys has been greatly facilitated by the work of Richard Harris and his keys to the Lichens of the Straits Counties, Michigan.
The Minnesota keys are mostly new with the
exceptions of the key to genera, key to the
pyrenolichens and key to Bacidia which are only some what modified from those of Harris.
However, all of these keys make use of some
of the information in the Michigan keys by Harris and his contribution is gratefully acknowledged.
The generic concepts are generally not as narrow as those of some workers but reference
is usually made to the placement in the smaller genera. However, generic limits are changing so rapidly it is almost impossible to keep up. A few species not yet found in Minnesota but likely to be found are included but enclosed in parentheses.
The 1998 revision adds some genera not included before, updates the nomenclature, corrects typographical errors and reformats the keys.
These keys are still arranged according to the old spore-based genera because many of the characters used to distinguish the newer small genera are difficult (ascus tips, HPLC, etc.). In most cases the smaller genera also have their own keys. A few of the old synonyms are also indicated until we learn what the new names are.
The 2005 revision adds a few keys and corrects some keys, nomenclature and errors.
Some of the recently reported species are not in the keys but are listed at the end before the index.